1. Field
The present invention relates to nanoparticles, conductive ink containing the nanoparticles, and a circuit line forming device using the conductive ink, and in particular, to nanoparticles, conductive ink, and a circuit line forming device for forming micro circuit lines.
2. Description of the Related Art
A method has recently been proposed of forming micro circuit lines on a substrate by the inkjet technique. This method allows selective forming of micro circuit lines to provide benefits in terms of time and economy. However, with the continued decrease in the size of electronic devices, there is a demand for even more microscopic circuit lines. However, satisfying the size of or the distance between wires required by the trend towards lighter and smaller devices is hindered by the problem of resolution in printing technology. Resolution depends on the diameter of the ink droplets ejected from the inkjet head and the surface tension and interfacial tension of the ink, but there is a limit to decreasing the size of the inkjet head or the diameter of the ejected droplets due to problems such as having to include metal nanoparticles for forming conductive circuit lines.
When ejecting ink by the inkjet technique, the problem of dispersion on the substrate is also an obstacle to forming micro circuit lines. Dispersion may differ according to dynamic properties such as the ejection speed, viscosity, and drying speed of the ink, the weight percentage of metal nanoparticles in the ink, and the surface properties of the substrate.
Also, as the ink droplets thus formed are dried, the metal particles are crowded at the edges due to transmittable flow caused by a difference in drying speeds, to form a coffee stain phenomenon. This causes a conductive or metallic migration phenomenon to consequently affect the reliability of the product.
Therefore, various attempts are being made to form micro patterns while forming wires with superior electrical reliability by the inkjet technique.